I need help to find the functional parts for a custom 40k airsoft

[vonHohenstein]

If this thread is in the wrong section, please move it where it belongs. I'm an engineer looking for advice, not a airsoft veteran.

 

Ok, I'm not into cosplay and not into airsoft. But I'm into "engineering stuff", 3D printing and Warhammer 40k. And this will become a airsoft-cosplay-crossover, so I need some advice.

 

I found this really cool cosplay probs on cults. They are optimised for 3D printing and just look great. But that's it. They don't shoot. I want to change that.

I could just buy any airsoft take it apart, measure the parts, modify the files, print them. Done. But then all the time I spend on redesign wouldn't benefit anyone else. And that's a waste.

 

So, I'm looking for an airsoft gun that is international available (there must be some big brands that ship everywhere), cheap (I want to keep the entry barrier low) and preferably available in different power levels.
It doesn't need to be a full gun, just the interior would be enough. And if there is one that can be bought with different power output (0,5J up to whatever is legal) but with the same mechanical dimensions, it would be perfect.
Oh, and it needs to have a short magazine, because I'll have to hide it in that small power cell.

The goal is to provide a set of STL files and a shopping list for everyone to build their own 40k themed airsoft gun. Can you help me with the shopping list?

 

The original designer knows about this. And he will distribute the modified files. I don't steal anyones IP

[Skara]

@Rogerborg have fun

[Tackle]

While I always like to see the effort people put in to the more obscure  airsoft builds, looking at those two pictured, can't help but notice the similarities between a Scar H & an 870 style shotgun ?.

Would it not be more practical to make dress up kits for recognised guns, after all the big names such as TM have done the hard work & are readily available, body kits that dress up the available guns, maybe 2 part clam shell style that wrap the bodies, retaining the strength (& financial value) of the model within.

Just a thought ? 🤔

[vonHohenstein]

To adujst the files, so I can fit the internals of a air soft gun inside is a lot simpler than adjusting them so I can fit a whole gun in them. And it's always going to look better if you have a complete redesign instead of a some bits glued to a existing gun.

And it's gonna be fun to make it. I'm neither into airsoft nor cosplay. The fun part for me is making it work. 

 

If I ever start working on a Bolter, it's probably ok, just to hide a full gun in it, because it's so large. But with the Lasgun, I don't want to make it too large.

Edited June 19 by vonHohenstein

[JinxDuh]

The Lucius pattern is basically a sci-fi BAR.

 

Entry level, easy to adjust, cheap - Sounds like a standard M4. Also matches the magazine profile with the 20 round VN style mags (Again, cheap)

[Rogerborg]

Oh, hello. This is very relevant to my interests.

 

I'd agree that an M4 makes sense as the base.  All you really need to retain is the lower receiver and gearbox, plus the hop unit and inner barrel, ideally as a complete unit.  Those are the shooty bits.

 

 

It shouldn't matter which M4, but with it being airsoft, it might, due to slight differences in dimensions.

 

CYMA would be the default choice to use for development as they're an actual OEM and should (there's that word again) be consistent across the range, from their cheapest plastic CM.5xx guns, up to the metal receivers with trick gearboxes and electronics.  However, there are many (many, many) other affordable options: Specna Arms, Lancer Tactical, Double Eagle, all of which have quick change springs (which the cheapest CYMAs don't) and any of which ought to be workable with perhaps some slight modification to the dimensions, either before printing or with some filing or filling afterwards.

 

What you'd want to print is the upper receiver. What matters is that it mates up with the lower - specifically keying into it at the rear, and at the front pin - and that the interior matches the original just above and in front of the magwell, where the hop unit seats.  That part is crucial to get right, as any misalignment of the hop unit, or inability to slide forwards and and backwards slightly, will result in misfeeds and/or magazines not seating.

 

You'll also need some sort of flip-or-slide-to-open window to access the hop unit dial, although it needn't be as big as the ejection port on the original receiver.

 

I'd suggest binning off the outer barrel and just run the inner barrel directly inside the printed receiver. The outer dimensions of airsoft inner barrels are fairly consistent, but I'd make the void a fraction bigger than your development gun's inner barrel, as the barrel can be (and commonly is) shimmed up with tape to fit snugly, on a case by case basis.  It's fine to have an inner barrel that's shorter than the outer, as long as it's not excessively so, and the BBs's don't impact the outer on the way out (which is another reason to make the void slightly oversized).

 

After that, you can go hog wild with the externals. For example, the CSI XM-5 is an M4 / V2 gearbox and hop unit inside a particularly funky plastic shell that... some people... already use as a space plasmalaser gun.

 

 

For the avoidance of doubt, I mention this as an example of what can be done with a full external factory do-over. I would not use this as the base gun for a kit!  It's not readily available now, and while the internals are V2 they're very sub-par. In theory it takes STANAG / M4 mags as well as its stock magazine, but the receiver halves and buffer tube are nothing like M4 compatible.  For all that it's just a hollow shell, it's a weighty boy too, and nobody wishes their gun was heavier come the end of the day, and it an absolute nightmare to take apart and work on.  It's a swing and a miss, you can do better by sticking with a stock lower and a simple one-pin takedown.

 

Oh, buffer tube. Some M4 have bolt-on buffer tubes, but the cheapest CYMAs don't, they're moulded to the back of the lower receiver.  However, the dimensions of the buffer tube itself should be... similar... and so you should be able to come up with a printed stock that secures onto most tubes.

 

Airsoft gearboxes can be front or rear wired.  With front wired, the wiring goes out past the hop unit (this can sometimes be a bit of a squeeze) to a battery somewhere in the upper receiver.  Rear wired, the wiring runs inside the buffer tube to a battery in the stock.  Rear wired is most common in generic M4s, and I'd suggest sticking with rear wiring, and keeping the battery inside the stock, with as much empty space as possible.

 

On magazines, I wouldn't sweat that just yet. There are a plethora of various short / low profile mags available, but magazine fitting and feeding is one of the common issues that airsofters encounter.  If you do get feeding issues, the most common cause is front to rear misalignment of the hop unit, or the nozzle protruding too far into the hop rubber, all of which is dependent on the magwell, magazine, hop unit, nozzle and hop rubber - it's a problem to solve on a case-by-case basis.

 

I'm looking forward to seeing what you come up with.  For development purposes, you don't even need a working gun, any boneyard basket-case should do, as long as it has all the external parts so that you can get the dimensions right.

[vonHohenstein]

Thanks for the detailed explanation.

 

Ok, so I will get a CYMA M4, take it apart and see how I can integrate the internals into the cosplay lasgun.

https://www.phenixairsoft.com/en/1083-m4-airsoft-replicas

There are a lot of CYMA M4s. Are the internals the same, or is there something I'd should look for?

Edited June 20 by vonHohenstein

[Rogerborg]

The shooting parts of airsoft M4s are mostly compatible and interchangeable, being based on reverse engineering Tokyo Marui guns.  All[*] M4s use the "V2" gearbox, which is as close to a standard as anything in airsoft, and the lower receiver, pistol grip, motor and hop units and barrels are also largely interchangeable.  That's why it doesn't particularly matter what you use as a base for development. If the printed parts fit on any M4 lower, then they should fit on every[*] M4 lower.

 

I suggested CYMA as they're cheap, tough, globally available, and a de facto standard. It's easy to get lost in airsoft makes and models, and get decision paralysis.

 

However, as adjustable power is a (sensible) goal, as an end user I'd be more likely to choose something with a quick change spring system as a base.  Since half the base gun is going to be discarded anyway, a Specna Arms SA-F03 FLEX (for example) would do fine.  It's really down to local prices and availability where you are - I mention Specna Arms as those are cheap and readily available in the UK, but it really won't matter what you get as long as it's TM / CYMA compatible.

 

This really is relevant to my interests, by the way, I play in Astra Militarum gear and have long been on the lookout for exactly what you're proposing to replace my current half-arsed solutions.

 

 

 

[*] There are exceptions at the higher end, like Systema, but the bulk of M4s are TM / CYMA compatible.

[vonHohenstein]

On 20/06/2024 at 11:42, Rogerborg said:

 

 

 

For the emperor! That's really cool. I'll send you the link as soon as the files are ready. At first I need to buy a M4. The CYMA are 100€, the Specna Arms 175€. So the choice is simple. I found a "Double Bell M4" for 55€. According to the description it has a V2 Gearbox and can take any TM compatible magazine. So it's also compatible to CYMA/TM? 55€ sound a lot better than 100€, especially considering I'm going to take it apart anyway

 

Have you ever heard about "42k LARP"? That seems to be EXACTLY your interest. Maybe it's worth a trip to northern Germany.

 

 

 

Edited June 21 by vonHohenstein

[Rogerborg]

On 21/06/2024 at 10:50, vonHohenstein said:

I found a "Double Bell M4" for 55€. According to the description it has a V2 Gearbox and can take any TM compatible magazine. So it's also compatible to CYMA/TM?

 

Hmm. It's cheap because it has a plastic gearbox, and is running at under half the power of a typical metal gearbox AEG, which likely means a light spring and a cheap motor.  However, as you only need it to get the dimensions right then it should do the job. It even sounds like it has a modern rotary hop unit rather than the older dial style - both types of unit are interchangeable, and taking TM mags is a good sign.

 

One consideration is that even the cheapest CYMAs come with a basic NiMh battery and charger, which will let you test the shooting performance. The Double Bell does not, so you'd have to spend extra on a battery and charger, which will push the price up by a surprising amount.

 

It's a pity you're not in the UK or I'd have sent you a M4 from the spares box.

 

That 42K LARP looks amazing, I'll look into that - thanks!

[vonHohenstein]

The very first step is done: 

I got the CAD files for the laspistol and will now modify it to hold a cheap laserpointer. This is a very first test on how hard/easy it is to modify STEP files, print them, test them etc.

Once that's done @Rogerborg will be able to built his most favorite cat toy 😉 and I will move on and start working on the lasgun.